Acciona, a Spanish construction group, could make four times as much money from selling its stake in power company Endesa to German rival E.On as it makes in a normal year from its building business.

Bankers close to the transaction, the largest announced last year, said Acciona will sell its stake to E.On, making a profit of €1.3bn ($1.7bn) in just five months. In 2005, the last year for which accounts are available, Acciona made net profits of €324m. One source close to Endesa said: "It is likely Acciona will accept, despite what it has previously said. It takes a long time to make that much money from construction."